Firearm stock with locking mechanism

ABSTRACT

A stock for a firearm is disclosed. The stock has a locking mechanism. The locking mechanism prevents the movement of the stock relative to a receiver extension. A locking member protrudes into a corresponding recess in the receiver extension, creating a detent arrangement. The locking member, a locating member, a crossbar, and a pin interact with one another and the stock to prevent disengagement of the detent arrangement.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application relates to and claims the benefit of U.S. Provisional Application No. 62/543,017 filed Aug. 9, 2017, the entire disclosure of which is hereby wholly incorporated by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND 1. Technical Field

The present disclosure relates to firearm components and accessories, and more particularly, to locking mechanisms for firearms stocks.

2. Description of the Related Art

Collapsible stocks for firearms have proven to have both advantages and disadvantages. A clear advantage is the capability to adjust length of pull to accommodate different shooters, or the same shooter in different circumstances. Another advantage is the relatively light weight one has over a fixed stock. This reduces the overall weight of the firearm and the reduced weight can make weapon manipulations easier. A disadvantage is that collapsible stocks historically have a noticeable amount of tolerance, rattle, or relative movement between the stock and a receiving member, such as a receiver extension or adapter, of the firearm. This has typically been deemed acceptable by manufacturers in the industry providing after-market stocks that are intended for use with a variety of firearms, because the manufacturers must accommodate the differences in standards that, even where purportedly working from the same pattern, do not necessarily adhere to the standardized dimensions of the particular pattern.

Undesirable movement or rattle can adversely affect stability and accuracy of the firearm to which the stock is mounted, and, importantly, affect the perception of quality of the stock and firearm, even if the accuracy is not necessarily affected. Over time, the relative movement can also lead to damage to the stock and/or the firearm.

The circumstances that would necessitate a change in the length of pull for a shooter are relatively rare, as is the transfer of a firearm between shooters. As such, beyond an initial adjustment, most collapsible stocks stay in the same position on the firearm for extended periods of time. Because the mechanism that allows the stock to be adjusted also introduces the movement in the stock, removing or modifying the mechanism may have the effect of removing the movement, while still retaining advantages, such a reduced weight.

Further, various states have statutes which limit certain firearms features. On such feature is the adjustability of a firearm stock. Commonly, these statutes prohibit stock adjustability when the adjustability is present in combination with various other firearm features designated by the statute. In locations where such a statute is in force, users wishing to retain the advantages of an adjustable stock must find a way to transform an adjustable stock in to a fixed stock in order to comply with the statute.

BRIEF SUMMARY

In accordance with aspects of the present disclosure, there may be provided a stock for a firearm, comprising a housing including a longitudinal axis fixed by a firing direction of the firearm, and a firearm engagement surface on an interior of the housing, the engagement surface configured to slidingly abut a receiving component of the firearm, the housing having a proximal end and a distal end. The stock may also include a shoulder plate attached to the proximal end of the housing, the shoulder plate configured to allow a user to brace the stock, and a distal end opening on the distal end of the housing, the end opening shaped to receive an end of the receiving component of the firearm. The stock may further include a pin holding bore passing through the stock and defining a diameter near one end of a locking mechanism bore in the stock, an opposite end of the locking bore in communication with the interior of the housing. The stock may also include a locking mechanism. The locking mechanism may include a locking member having a bore extending from an opening at a first end of the locking member to wall near a second end of the locking member, the bore defining a locking member interior, the locking member located in the locking mechanism bore in the stock. The locking mechanism may also include a crossbar located in a crossbar bore in the locking member, the crossbar having a friction engagement with an exterior surface of the stock, and a locating member located in the locking member interior, one end of the locking member having a friction engagement with the crossbar, the locating member having a cross bore defining a diameter near an opposite end of the locating member. The locking mechanism may also include a pin located in the pin holding bore and locating member cross bore.

In accordance with further aspects of the present disclosure, there may be provided a stock for a firearm, comprising a housing having a proximal end and a distal end and a hollow interior extending therebetween, and a holding bore passing through the stock and defining a diameter near one end of a locking bore, an opposite end of the locking bore in communication with the interior of the housing. The stock may also include a locking mechanism. The locking mechanism may include a locking shaft. The locking shaft may include a sleeve, the sleeve including a bore extending from an opening at a first end of the sleeve to wall near a second end of the sleeve, the bore defining a sleeve interior, the sleeve located in the locking mechanism bore in the stock, and a rod located in the sleeve interior, one end of the rod having a friction engagement with the crossbar, the rod having a cross bore defining a diameter near an opposite end of the locating member. The stock may further include a first cross piece located in a crossbar bore in the sleeve, the sleeve having a friction engagement with an exterior surface of the stock, and a second cross piece located in the holding bore and rod cross bore.

In accordance with further aspects of the present disclosure, there may be provided a stock for a firearm, comprising a stock frame including a housing configured to receive a firearm receiver extension, a shoulder plate, a locking mechanism bore defining a locking mechanism bore longitudinal axis, the locking mechanism bore in communication with an interior of the tube housing; and a holding bore perpendicular defining a holding bore longitudinal axis perpendicular to the locking mechanism bore longitudinal axis. The stock for a firearm may also include means for preventing movement of the stock relative to the firearm receiver extension.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

FIG. 1 shows a perspective view of the receiver extension and stock, including the locking mechanism;

FIG. 2 shows an exploded view of the receiver extension and stock, including the locking mechanism of FIG. 1;

FIG. 3A shows an exploded perspective view of locking mechanism;

FIG. 3B shows a perspective view of a locating member; and

FIG. 4 shows a cross sectional view at line 4-4 in FIG. 2.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments of a machining tool assembly for a firearm lower receiver and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structure(s) and/or functions in connection with the illustrated embodiments, but it is to be understood, however, that the same or equivalent structure and/or functions may be accomplished by different embodiments that are also intended to be encompassed within the scope of the present disclosure. It is further understood that the use of relational terms such as first and second, and the like are used solely to distinguish one entity from another without necessarily requiring or implying any actual such relationship or order between such entities.

Referring to FIGS. 1-4, aspects of a stock 100 for a firearm which retains advantages of an adjustable stock, while eliminating the primary cause of unwanted movement between the stock 100 and the receiver extension 200 of the firearm are disclosed.

With reference now to FIGS. 1-2, an exemplary stock 100 for a firearm (not shown) in connection with which various embodiments of the presently disclosed compliance device may be utilized is now described in detail. The stock 100 may include a housing 102. The housing 102 may be defined by proximal end 104 and an opposed distal end 106. The distal end 106 of the housing may include an opening 108 sized and shaped to receive a receiver extension 110 of the firearm. The receiver extension 110 may house a buffer and buffer spring, which may absorb some recoil of the firearm. The receiver extension 110 may define a longitudinal axis FA. The longitudinal axis FA may be parallel to a firing direction of the firearm.

The receiver extension 110 interfaces with the bolt carrier group in AR-15 style firearms. The bolt carrier group may include the bolt and bolt carrier. The bolt carrier group may move in a reciprocating motion. The reciprocating motion may be divided in to a first portion and a second portion. When the bolt carrier group is in a firing position, a firing pin in the bolt may strike a primer of a round, igniting the primer, and, in turn, the power charge of a round. The powder charge burns, turning the powder to gas and propelling the bullet out of the barrel. Some of the gasses propelling the bullet may be captured, and diverted back, via a gas tube, to the bolt carrier. The gas pressure from the gas in the gas tube may propel the bolt carrier group rearward, in a first portion of the reciprocal motion. As the bolt carrier group moves rearward, it may contact the buffer. The buffer may be biased in to a position at a distal end of the receiver extension by the buffer spring. When the bolt carrier group contacts the buffer, the force of the bolt carrier group may counteract the bias force of the buffer spring. As the first portion of the reciprocal motion continues, the momentum of the bolt carrier group may dissipate, and the force provided by the bolt carrier group may become equivalent to the bias force of the buffer spring.

When the force provided by the gas through the bolt carrier group and the bias force of the buffer spring are equal, the reciprocal motion may transition from a first portion to a second portion. Correspondingly, as the bias force of the buffer spring becomes greater than the force provided by the gas, the bolt carrier group may reverse direction, as it is accelerated by the force of the buffer spring. As the bolt carrier group moves forward, a face of the bolt may contact a rear of a round at the top of a magazine inserted in a magazine well of the receiver. The bolt may grab the round, moving the round forward in front of the bolt. The round may move up a feed ramp and in to a chamber in a rear portion of a barrel. When the round and bolt face are seated at a rear of the chamber, the second portion may be complete.

When there may be no round remaining in the magazine, a follower in the magazine moves to the top of an interior of the magazine, biased from below by a follower spring. The follower contacts a bolt catch and moves it upward. The bolt catch blocks the forward motion of the bolt carrier group just as it arrives at the transition point, leaving the bolt open.

As best seen in FIG. 2, the opening 108 may have a circular keyed shape. That is, the opening 108 may be generally circular, defining a circumference. The circumference may include, at one point, a radial extension portion 112. The radial extension portion 112 may be in the shape of a square. The opening 108 is thus shaped so that the receiver extension 110 and stock 100 may only be joined with a particular orientation relative to one another, and prevent significant rotational movement of the stock 100 about the axis FA. It is understood that the radial extension 112 may also be of other shapes, for example, a triangle, a semicircle, a half hexagon, or any other shape which achieves the purpose of aligning the stock 100 and receiver extension 110 relative to one another. It will be understood, however, that the shape and size of the receiver extension 110 is standardized.

The proximal end 104 of the housing 102 may attach to a shoulder plate 114. The shoulder plate 114 may include an interior side 116 and an exterior side 118. The shoulder plate 114 may attach to the proximal end 104 of the housing 102 near a first end 120 of the shoulder plate 114 on the interior side 116.

The housing 102 may define a longitudinal axis extending from the proximal end 104 to the distal end 106. The housing may define an interior 122. The interior 122 may include an interior surface 124 which may face an outer surface 126 of the receiver extension 110. A locking mechanism portion 137 of the stock may extend radially outward from the housing 102 in a direction perpendicular to the longitudinal axis FA of the housing 102. The portion 137 of the stock 100 may include a wall 135. The wall 135 is defined on one side by an exterior surface 138 of the stock 100 on an opposite side by an interior surface 132. The interior surface may define a locking mechanism bore 130, which may have a generally cylindrical shape. The locking mechanism bore 130 generally cylindrical shape defines a circumference. An opening 128 on one end of the locking mechanism bore 130 opens in to the interior 122 of the housing 102.

The stock 100 may further include pin holding holes 134 near an end opposite the end of the locking mechanism bore 130. The pin holding holes 134 may be on opposing points of the circumference defined by the locking mechanism bore 130. A longitudinal axis between the pin holding holes 134 may be perpendicular to the longitudinal axis of the locking mechanism bore 130, and may define a diameter of the locking mechanism bore 130. Longitudinal slots 136 may be formed in the wall 135. The longitudinal slots 136 may be on opposing points of the circumference of the locking mechanism bore 130. The longitudinal slots 136 may open on to the interior 132 of the locking mechanism bore 130, and on an opposite side of the longitudinal slots 136, open on an exterior surface 138 of the stock 100. The longitudinal slots 136 may have curved ends.

The stock 100 may further include a brace or strut 140 extending from the locking mechanism portion 137 to the interior side 116 of the shoulder plate 114 on an end opposite the end of the shoulder plate 114 which connects to the housing 102. The brace 140 serves to stiffen the stock 100. The stiffening prevents deformation of the stock 100 when the firearm is fired with the firearm braced against a user's shoulder.

As best shown in FIGS. 2, 3A, and 3B, a locking mechanism 144 may be sized and shaped to be receivably engaged with the locking mechanism bore 130. The locking mechanism 144 may include a locking member 146, which may also be referenced as a sleeve. The locking member 146 may be generally cylindrical in shape, and define a longitudinal axis LA as well as a circumference. The locking member or sleeve 146 may be divided in to two sections along the longitudinal axis LA. A first section 148 may be solid and may have a smaller diameter, and corresponding circumference, compared to a second section 150.

The second section 150 may have a diameter larger than the first section 148. The second section may include a cylindrical wall 166. The cylindrical wall 166 may have an exterior surface 164, and an interior surface 159. The second section 150 may include a bore defining a second section interior 158. An end 160 of second section 150, which is also an end of the locking member 146, may include an opening 162. The second section interior 158 extends from the opening 162 to the boundary of the first section 148 and second section 150.

The second section 150 may include cross holes 152. The cross holes 152 may pass through the cylindrical wall 166, opening on one side to the exterior surface 164 and on the other side to the second section interior 158. Each of the cross holes 152 may be on at a point opposite the other on the circumference of the radial wall 166.

The second section 150 may also include longitudinal slots 156. Similar to the cross holes 152, the longitudinal slots 156 may open on one side to the exterior 164, and on the other side to the second section interior 158.

The crossbar or crosspiece 154 may be generally cylindrically shaped. An outer diameter of the crossbar 154 may be substantially equivalent to the inner diameter of the cross holes 152. The crossbar 154 may further include a notch or recess 168. The notch or recess 168 may extend across a first diameter of the crossbar 154 in a cross section viewed along a longitudinal axis of the crossbar 154, and halfway through the cross section of the crossbar 154 along a second diameter, perpendicular to the first diameter. The notch 168 may be sized and shaped to receive and hold a first end 172 of a locating rod 170. A radius of the crossbar or crosspiece 154 may be substantially equal to a radius of the curved end of the longitudinal slots 136.

The locating rod 170 may be generally cylindrical. An outer diameter of the locating rod 170 may be substantially equal to a diameter of the second section interior 158. For example, the outer diameter of the locating member 170 may be 5.5 mm. The locating rod 170 may also have a length substantially equal to a length of the second section interior 158 minus a half diameter of the crossbar 154. For example, the locating member or rod 170 may be 25 mm in length. The locating rod 170 may have a bore 174 which passes through a cross section of the locating member or rod 170. The locating rod bore 174 diameter may be 2.6 mm, for example. A path of the locating rod bore 174 may define a diameter of the locating rod 170. The locating rod bore 174 may be spaced from a second end 176 of the locating rod 170 such that the locating bore 174 aligns with the pin holding holes 134. For example, the locating rod bore 174 may be spaced 4.55 mm on center, or 3.33 mm to the point on a circumference of the locating rod bore 174 closest to the second end 176 of the locating member 170. Alternatively, as shown in FIG. 3B, the locating rod 170′ may taper from widest at the end near the locating member bore to narrowest at the opposite end. The taper creates an angle T from the circumference of the second end 176′ of the locating rod 170′. The locating rod 170 may also be hollow. The locating rod 170 may be made of any material with sufficient material strength to allow the locking mechanism to retain structural integrity. For example, the locating rod 170 may be made of steel, aluminum, or polymer.

The locating rod 170 may be placed in the second section interior 158 of the locking member or sleeve 146. The combination of the locking member 146 and locating member 170, and their placement in the locking mechanism bore 130 may cause the pin holding holes 134, the longitudinal slots 156 on the locking member 146, and the locating rod bore 174 to form a common bore, through which a pin or cross piece 180 may be passed. The combination of the locking member 146 and the locating member 170 may be called a locking shaft 145. The pin or cross piece 180 may be a hollow pin, for example, a roll pin, or may be a solid pin, generally cylindrical in shape. However, other shapes for the pin or cross piece 180 are contemplated.

As may be best shown in FIGS. 3A and 4, in use, the housing 102 may be placed on the receiver extension 110 and the opening 128 in the housing interior 122 aligned with a corresponding recess 182 in the receiver extension 110. Next, the locking member 146 may be inserted partially in the locking mechanism bore 130. The crossbar or first cross piece 154 may be then inserted through the longitudinal slots 136 stock 100 and through the crossbar holes 152 in the locking member second section 150. The notch 168 in the cross bar or first cross piece 154 may be aligned with the second section interior 158 and the notch 168 facing in to the second section interior 158. The locating rod 170 then may be inserted in to the second section interior 158. The locating rod 170 may be inserted and the crossbar or first cross piece 154 oriented such that the first end the locating rod 170 engages the notch 168 in a friction engagement. The sub-assembly of the locking member 150, the crossbar 154, and the locating rod 170 may then be advanced fully in to the locking mechanism bore 130. The locating rod 170 is oriented so that the pin holding holes 134 in the stock 100 and the locating member bore 174 form a common bore. Finally, the pin, or second cross piece 180 may then be inserted through one of the pin holding holes 134, through the locating member bore 174, and through the opposite pin holding hole 134. The insertion of the pin 180 to the pin holding holes 134 and locating member bore 174 may lock the locking mechanism 144 in place. Once the locking mechanism 144 may be locked in place, the first section 148 of the locking member 146 may extend through the locking mechanism bore opening 128 in the interior 122 of the housing 102, and also in to the corresponding recess 182 in the receiver extension 110. The interaction of the first section 148 of the locking member 146 and the recess 182 may be a detent arrangement. The engagement between the locking member 146 and the receiver extension 110 on one end, and the pin 180, stock 100, and locating member 170 on an opposite end, may hold the locking mechanism 144 in place, and may prevent the stock 100 from moving relative to the receiver extension 110.

The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of forming the locating member or rod. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments. 

What is claimed is:
 1. A stock for a firearm, comprising: a housing defined by a longitudinal axis aligned with a firing direction of the firearm and having a proximal end and a distal end, the housing being further defined by a firearm engagement surface on an interior of the housing and configured to slidingly abut a receiving component of the firearm; a shoulder plate disposed on the proximal end of the housing and configured to allow a user to brace the stock; a distal end opening on the distal end of the housing, the distal end opening shaped to receive an end of the receiving component of the firearm; a pin holding bore extending through the stock and defining a diameter near one end of a locking mechanism bore in the stock, an opposite end of the locking bore in communication with the interior of the housing; and a locking mechanism, including: a locking member defining a locking member bore extending from an opening at a first end of the locking member to a second end of the locking member, and a crossbar bore normal to the locking member bore, the locking member being received within the locking mechanism bore in the stock; a crossbar disposed in the crossbar bore in the locking member and being in engagement with the stock; a locating member in the locking member bore, one end of the locking member being in receptive engagement with the crossbar, the locating member further defining a cross bore with an opening proximal to an opposite end of the locating member; and a pin disposed in the pin holding bore and the locating member cross bore.
 2. The stock of claim 1, wherein the pin holding bore and the locating member cross bore form a common bore.
 3. The stock of claim 1, wherein the locking member has a generally cylindrical shape defining a circumference.
 4. The stock of claim 3, further comprising two longitudinal slots, one each on opposing points of the circumference of the of the locking member.
 5. The stock of claim 1, wherein the locking member further includes a locking section on a second end of the locking member.
 6. The stock of claim 5, wherein the locking section extends from the locking mechanism bore in to the interior of the housing.
 7. The stock of claim 1, wherein the crossbar further includes a center notch sized and shaped to engage the one end of the locating member.
 8. The stock of claim 5, wherein the locating member has a length of 25 mm.
 9. The stock of claim 1, wherein the locating member has a diameter of 5.5 mm.
 10. The stock of claim 1, wherein the first end of the locking member includes a taper which matches a taper in a cross piece between the housing and the shoulder plate.
 11. A stock for a firearm, comprising: a housing with a proximal end, a distal end, and a hollow interior therebetween; a holding bore extending through the stock and defining a diameter near one end of a locking bore, an opposite end of the locking bore being in communication with the hollow interior of the housing; and a locking mechanism, including: a locking shaft with a sleeve defining a bore extending from an opening at a first end to a wall proximal to a second end thereof, the sleeve being located in the locking mechanism bore in the stock, and a rod disposed in the bore of the sleeve, one end of the rod being in receptive engagement with the crossbar, the rod defining a cross bore with a diameter near an opposite end of the locating member; a first cross piece disposed in a crossbar bore in the sleeve, the sleeve being in receptive engagement with the stock; and a second cross piece located in the holding bore and the cross bore of the rod.
 12. The stock of claim 11, wherein the sleeve has a generally cylindrical shape including a circumference.
 13. The stock of claim 12, further comprising two longitudinal slots, one each on opposing points of the circumference of the of the sleeve.
 14. The stock of claim 11, wherein the pin has a cylindrical shape, including a consistent diameter from the one end to the opposite end.
 15. The stock of claim 11, wherein the pin has a circular cross section which tapers from smaller at the one end to larger at the opposite end.
 16. The stock of claim 11, wherein the sleeve and pin are formed as a single piece.
 17. The stock of claim 16, wherein the an outer diameter of the second cross piece and an inner diameter of the pin cross bore are substantially equal.
 18. A stock for a firearm, comprising: a stock frame including a housing configured to receive a firearm receiver extension, a shoulder plate, a locking mechanism bore defining a locking mechanism bore longitudinal axis, the locking mechanism bore in communication with an interior of the tube housing; and a holding bore perpendicular defining a holding bore longitudinal axis perpendicular to the locking mechanism bore longitudinal axis; means for preventing movement of the stock relative to the firearm receiver extension.
 19. The stock of claim 18, wherein the means for preventing movement of the stock relative to the firearm receiver extension extend from the locking mechanism bore in to the interior of the tube housing.
 20. The stock of claim 18, wherein the locking mechanism bore further includes two slots opposite one another, the two slots oriented such that a longitudinal axis of the slots is parallel to a longitudinal axis of the locking mechanism bore. 